Analysis and Design of a Sub-THz >100Gbps CMOS RF-64QAM Transmitter with On-Chip Antenna for FutureG Wireless Links
Abstract
FutureG wireless communication aims for data transmission rates of hundreds of gigabits per second (Gbps), utilizing the extensive bandwidth within the sub-terahertz (sub-THz) spectrum and higher-order modulation schemes such as 64QAM to enhance spectral efficiency. Conventional transmitter (TX) architectures face significant challenges at these data rates, especially from power amplifier (PA) design issues like efficiency degradation and AM-PM distortion.
This research introduces a bits-to-antenna RF-64QAM TX that constructs the 64QAM constellation directly in the RF domain using three QPSK sub-TXs with weighted amplitude, effectively countering PA nonlinearity challenges. To this end, a sub-THz TX prototype fabricated in 45nm CMOS SOI is presented, showcasing a 40-GHz RF bandwidth, with a measured data rate of 120 Gbps, and an effective isotropic radiated power (EIRP) of 16 dBm, paving the way for next-generation wireless communication.